Woven bar screen.



W. S. POTTER.

WOVEN BAR SCREEN. APPLICATION FILED MAY 2,1913.

1,139,,Qfi8; Patented May 11, 1915.

2 SHEETS-SHEET l.

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W. S. POTTER.

WOVEN BAR SCREEN.

APPLICATION FILED MAY 2. 1913.

1 139A68 Patented May 11, 1915.

2 SHEETS-SHEET 2.

UNITED BTATEB PAENT @FFIQE.

WINFIELD S. POTTER, OF PITTSBURGH, PENNSYLVANIA.

WOVEN BAR SCREEN.

isaaes.

Application filed May 2, 1913.

T 0 all whom it may concern Be it known that I, VVINFIELD Soo'rr Po'r- TER, a citizen of the United States, residing at Pittsburgh, county of Allegheny, State of Pennsylvania, (whose post-oflice address is Manufacturers Building, Duquesne IVay, Pittsburgh, Pennsylvania,) have invented certain new and useful Improvements in I'Voven Bar Screens; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention provides a type of woven metallic screen which, in different specific embodiments of the same fundamental and characteristic principles of construc tion, has a wide range of applicability to various kinds of screening operations, including the screening operations in which cold crimped round rod screens are commonly employed, as well as those in which punched perforated plate screens are now used; and which marks a substantial improvement upon these old types of screens in maintenance of accurate size of screen ing opening, in durability and in other respects which will appear more fully from the following description.

In accordance with the invention the rod or bar elements which are to be interwoven to form the assembled screen are subjected to a process of hot bending or forming, supplemented in some cases by subsequent cold crimping, such as to produce at the points of crossing relatively deep and abrupt depressions or indentations in which the intersecting bars or rods are substantially embedded. Furthermore, in constructing the screen, rods or bars are employed of generally rectangular outline or at least flat on that face which lies on the screening surface of the assembled screen. This construction has the advantage that lateral displacement of the intersecting rods is impossible and preservation of the original accurate mesh sizes during the whole life of the screen is thereby assured; and it may have the further advantage, where the recesses or depressions are of suflicient depth and proper contour to permit the intersecting bars to be embedded to their full vertical depth below the screening surface of the assembled screen, that the roughness primarily due to the insuflicient bending of the ordinary Woven cold crimped round rod Specification of Letters Patent.

Patented May 11, 1915.

Serial No. 765,040.

screens is avoided and the screen thereby made more suitable for many screening operations such as the screening of coke, where the bounding about of the screened material resulting from the irregular surface interferes with or prevents that accurate grading of the material which it is the object of the screening operation to effect.

For a great many industrial purposes, it is of added advantage to carry out the same principles of construction with bars of ob long section, that is, bars having a depth substantially exceeding their width. By this expedient it becomes possible to make the bars much narrower, while still retaining the necessary strength and rigidity, thereby substantially increasing the effective screening area per unit of screen surface, and by reason of the added depth of the bars, greatly increasing the life of the screen.

The improved type of screen furthermore retains all the advantages incident to woven screens of wrought metal, as compared with punched screens or screens cast in units or made up of spaced cast bars, while at the same time making possible the construction of screens having extremely narrow mesh openings such as are required for some classes of work.

In the drawings, Figure 1 illustrates in perspective; Fig. 2 in plan; and Fig. 3 in cross-section, a simple but strong construction of fiat surface screen in accordance with the invention; Fig. 4; shows in elevation one of the bars from which this screen is made up; and Figs. 5 and 6, indicate possibilities of variation in the configuration of the bars; Figs. 7, 8 and 9, illustrate a construction which may conveniently be adopted for making screens of narrow mesh; Fig. 7 being a plan of a portion of a completed screen; Fig. 8 an elevation of a longitudinal bar and Fig. 9, an elevation of a cross-bar.

In the screen illustrated in the Figs. 1, 2, 3 and 4, the woven bars 1 have a simple keystone cross-section and are rolled or forged to form sharp recesses or depressions 2 spaced apart a distance equal to twice the distance between centers of the screen orifices, the depressions or recesses being of such configuration as to receive and preferably, though not necessarily, to closely embrace the crossing bar as best shown in F ig. 3. The assembled screen is made up from such bars by an ordinary process of weaving, as will be readily understood by those skilled in the art. The keystone section gives good clearance and is easily modified so that its upper portion has substantially parallel sides merging into the key thickness at the base of the recesses is, as

indicated at much less than the depth of the bar. Such a configuration produces a bar whichhasincreased flexibility and is consequently more easily woven, and yet is of quite adequate strength for many uses. his, in' fact, only necessary to make the thickness at the base of the recesses substantially equal to the average minimum thicknessto which the screen plate may be worn before the portions of the bars between recesses; become too thin to withstand the strains incident to use, and it becomes necessary to discard the screen. If, on the other hand, it is desirable to have a particularly stiff and rigid structure, the configuratonillustratedin Fig. 6 may be adopted; In this configuration, the body of the bar isshaped or formed with recesses or depressions on its opposite sides, the recesses 7 on theunder side, being large enough at their bases to embrace the tops of the cross,- ing bars. Such a configurationis less easily woven, but has substantial advantages for some types of screen.

By substituting for the keystone crosssecti'onof the bars a cross-section which has a rounded under surface, and giving to the recesses a corresponding shape, as illustrated in Fig. 5, at 4. and 5, a bar is produced which is lighter and more easily woven than a bar of the configuration shown in Fig. 4, and at-the same-time, the screen made of such bars ha'sexcel'lent clearance.

It is often desirable to' produce screens having-a mesh: sosmall that the weaving operation requires a greater flexure of the bars than they will stand or than could be readily given to them. In such cases, I adopt a construction corresponding in principle-tothat'illustrated' in Figs. 7, 8 and 9. These -figuresillustratebut one typical form of small mesh screen, the particular instanceseleeted for illustration being one in which theopenings' have a greater length than width,:-blut itwill be understood that the openings may be -made square or of any; iother desired rectangular outline by properly varying the position of the notches.

are so located that the alternately overlapping and underlapping sections of the woven bars embrace respectively a plurality of-intersecting bars. Thus, in Fig. 7, the longitudinal bars 8 have, on-the upper side,- two notches 9, then onthe under side two notches 10, and so on, while some of the cross-bars 11 may have, on the upper side, say four notches 12 and then on the under side say two notches 13, and so on, the remaining cross-bars having on the upper side say two, and on-the under side say four notches, and so on; it being understood that the number of successive notches on the same side of the bar may be varied to suit particular conditions.

. The screens so constructed may be woven with rectangular or diagonal mesh'openings of any desired length and width, and fulfil, in their many possible specifically different embodi1nents,all of the requirements of the trade with respect to character of screening surface, while retaining at all times the desirable accuracy of mesh openings. They may be made in sections correspondingin size to the punched plate sections now on the market but have the great advantage r over punched plate screens that they may be made of relative great thickness and correspondingly long life, and the waste of material represented by the punched-,out

pieces and the loss due to cracking incident to the punching and bending operations, is avoided. The improved screens will, however, preferably be made in a single piece measured lengthwise or circumferentially,

which will have a greater percentage of ef- I fective screening surface both on account of the omission of fastenings and marginal strips required in sectional plate screens, and on account of less width of the sections of metal between the mesh openings. screens may be woven into assembled screens of any practicable curvature, or they may be woven flat and then rolled to the desired curvature. In this way, for example, cylin- The drical revolving screens, which are now widely used, can be cheaply manufactured and can be'given great strength and durability. I

Fromwhat has been said it willbe understood that the recesses or depressions may be'made'to conform'to the section of the in-' tersecting bar both as to depth and side contour so thatthe intersecting bar is held in theintended position without danger of dis placement and may be let in vertically a portion of its' depth, its 1 entire: depth, or more than its entire depth, so that it will be below the top line of the bar having the recess. In this way the top lines of all bars may be flush with the screening surface, or some bars may stand above others. Thus, it will sometimes be of advantage to make more prominent the bars running in the direction in which the screened materials flow. So also it is often advisable to make the bars running in the two directions of different section, as will be readily understood.

What I claim is:

1. A screen made up of interwoven wrought metal bars having fiat upper surfaces and shaped to present at the points of crossing abrupt recesses 0r depressions of suflicient depth to let in the full vertical depth of the intersecting bars, thereby presenting a screening surface devoid of substantial irregularities; substantially as described.

2. A screen made up of interwoven wrought metal bars shaped to present at the points of crossing abrupt recesses or depressions securely interlocking the intersecting bars against displacement, the recesses or depressions being so arranged that the alternately overlapping and underlapping sections'of the woven bars contain a plurality of recesses embracing in a single section a plurality of the intersecting bars; substantially as described.

3. A screen made up of interwoven wrought metal bars having flat upper and under surfaces and shaped to present at the points of crossing abrupt complementary interfitting recesses or depressions, the combined depth of each pair of interfitting recesses or depressions being equal to the full vertical depth of the intersecting bars, thereby presenting on both sides of the screen a screening surface devoid of substantial irregularities.

4. A screen made up of interwoven wrought metal bars of which the vertical depth substantially exceeds the thickness and which are shaped to present at the points of crossing abrupt recesses or depressions securely interlocking the intersecting bars against displacement; substantially as described.

In testimony whereof I affix my signature, in presence of two witnesses.

WINFIELD S. POTTER. l/Vitnesses:

E. V. D. JOHNSTON, H. C. HANCOCK.

Copies of this patent may beobtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

